Your 4th Week

The uterine lining secretes hormones that help to support the pregnancy.

Chorionic cavity

The yolk sac is forming. It will nourish the embryo until the placenta starts functioning and make blood cells until the liver can do this.

The placenta starts to develop here. Soon the cells will penetrate the lining of the uterus.

The embryo consists of just two layers of cells that will divide very rapidly to form the beginnings of the baby's body.

The amniotic cavity, which later becomes the fluid-filled amniotic sac that protects the baby, develops from this area.

The embryo-to-be, now securely implanted in the lining of your uterus, is starting to develop. Although you could do a home pregnancy test this week, you may end up disappointed or uncertain because at this stage a definite result is unlikely. It can be nerve racking, wondering if an unwanted period is about to arrive and dash your hopes. Talk to your partner and share your feelings with him-he may be anxious, too.